A major problem arising in the use of an uninterruptable power supply (UPS) occurs when harmonic distortion is induced within the output voltage signal. Uninterruptable power sources typically have a high source impedance when looking back into the device from the UPS output terminals that promotes harmonic distortions.
One currently utilized method for eliminating harmonic distortions in the output voltage of a UPS comprises the use of low-impedance notch filters coupled to the UPS output. These filters decrease the output impedance of the power supply at the resonant frequency and consequently decrease the harmonic distortion induced in the output voltage signal. However, the use of the bulky hardware components required for the filters adds to the size and weight of a UPS and increases the possibility of failure of the UPS due to the breakdown of a component. Thus, a need has arisen for a system for correcting harmonic distortion that does not substantially increase the size, weight and reliability of an uninterruptable power source.